Different sector rotation speeds for post-amble processing of a beam forming packet

ABSTRACT

Post-amble processing of a beam forming packet may utilize different sector rotation speeds at different wireless communication devices. Power measurements may be captured for individual sectors of an antenna array with respect to a complete rotation of antenna sectors at another wireless communication device. The power measurements may be evaluated to identify a sector for directing a millimeter wave beam between the different wireless communication devices. In some embodiments, a second packet may be transmitted back using the identified sector to determine another sector for directing the millimeter wave beam between the different wireless communication devices.

TECHNICAL FIELD

This disclosure relates generally to wireless communication systems andtechniques for directing directional wave signals between components ofa wireless communication system.

BACKGROUND

Wireless communication systems are increasingly widespread.Additionally, there exist numerous different wireless communicationtechnologies and standards. Some examples of wireless communicationstandards include IEEE 802.11 (WLAN or Wi-Fi, for example 802.11a/b/g/n/ac/ax in the frequency band of 2.4 and/or 5 GHz, and 802.11ad/ay in the band of 60 GHz), IEEE 802.15 (WPAN), IEEE 802.16 (WiMAX),and others.

Furthermore, as applications and devices continue to require higherlevels of throughput for wireless communications, higher frequency wavesare being used to transmit more data. For example, IEEE 802.11 adprovides for gigabit per second speeds using 60 GHz frequency bandmillimeter waves. However, high frequency waves, such as 60 GHz waves,cannot typically penetrate effectively walls or other solid structures.Also, such high-frequency waves may have greater decay because thereception of such waves may not be effectively received at otherantennas than lower frequency waves, such that a range of a transmittertransmitting such high-frequency waves may be reduced as compared to atransmitter transmitting lower frequency waves.

In some wireless communication systems using high-frequency waves, suchas 60 GHZ waves, beam forming techniques may be used to direct ahigh-frequency wave toward an intended receiver. Even if a clearline-of-sight is not available, the beam forming techniques may directthe wave via reflections toward an intended receiver. Additionally, if aline-of-sight of an established link between a transmitter and receiverbecomes suddenly blocked, such systems may lose communication fornon-trivial amounts of time while searching for new directions. Themovement and rotation of the receiver or transmitter may require furtherbeam forming operations to direct the signal.

SUMMARY

In various embodiments, different sector rotation speeds for post-ambleprocessing of a beam forming packet may be implemented. Beam formingtechniques may be implemented to identify optimal wireless beams toestablish communication links between wireless computing devices.Wireless signals may be directed or shaped in different directions toobtain better signal strength to enhance performance between thewireless communication devices. As wireless communication devices maymove, or blocking objects or signals may change the interference in agiven location, optimal wireless beams may be identified to adapt to orotherwise overcome interference or blockage between wirelesscommunication devices. In order to quickly restore communications thatfailed or degraded between two wireless communication devices, therotation speeds for processing a beam forming packet to determine anoptimal wireless beam may be different in order to capture powermeasurements between the different sectors of antenna arrays accordingto information in a post-amble portion of a single packet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate different sector rotation speeds for post-ambleprocessing of a beam forming packet, according to some embodiments.

FIG. 2 illustrates a wireless communication device that implementsdifferent sector rotation speeds for post-amble processing of a beamforming packet, according to some embodiments, according to someembodiments.

FIG. 3 illustrates example beam forming packets that may be transmittedimplementing different sector rotation speeds for post-amble processingof a beam forming packet, according to some embodiments.

FIG. 4 is a high-level flowchart illustrating various methods andtechniques to implement different sector rotation speeds for post-ambleprocessing of a beam forming packet, according to some embodiments.

FIG. 5 is a high-level flowchart illustrating various methods andtechniques to implement selecting an optimal reception sector at aresponder receiving a packet of a beam forming protocol, according tosome embodiments.

FIG. 6 is a high-level flowchart illustrating various methods andtechniques to selecting an optimal transmission sector for an initiatorof a beam forming protocol, according to some embodiments.

FIG. 7 is a logical block diagram of an example computer system,according to some embodiments.

This specification includes references to “one embodiment” or “anembodiment.” The appearances of the phrases “in one embodiment” or “inan embodiment” do not necessarily refer to the same embodiment.Particular features, structures, or characteristics may be combined inany suitable manner consistent with this disclosure.

“Comprising.” This term is open-ended. As used in the appended claims,this term does not foreclose additional structure or steps. Consider aclaim that recites: “An apparatus comprising one or more processor units. . . .” Such a claim does not foreclose the apparatus from includingadditional components (e.g., a network interface unit, graphicscircuitry, etc.).

“Configured To.” Various units, circuits, or other components may bedescribed or claimed as “configured to” perform a task or tasks. In suchcontexts, “configured to” is used to connote structure by indicatingthat the units/circuits/components include structure (e.g., circuitry)that performs those task or tasks during operation. As such, theunit/circuit/component can be said to be configured to perform the taskeven when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. § 112(f) for that unit/circuit/component. Additionally,“configured to” can include generic structure (e.g., generic circuitry)that is manipulated by software and/or firmware (e.g., an FPGA or ageneral-purpose processor executing software) to operate in manner thatis capable of performing the task(s) at issue. “Configure to” may alsoinclude adapting a manufacturing process (e.g., a semiconductorfabrication facility) to fabricate devices (e.g., integrated circuits)that are adapted to implement or perform one or more tasks.

“First,” “Second,” etc. As used herein, these terms are used as labelsfor nouns that they precede, and do not imply any type of ordering(e.g., spatial, temporal, logical, etc.). For example, a buffer circuitmay be described herein as performing write operations for “first” and“second” values. The terms “first” and “second” do not necessarily implythat the first value must be written before the second value.

“Based On.” As used herein, this term is used to describe one or morefactors that affect a determination. This term does not forecloseadditional factors that may affect a determination. That is, adetermination may be solely based on those factors or based, at least inpart, on those factors. Consider the phrase “determine A based on B.”While in this case, B is a factor that affects the determination of A,such a phrase does not foreclose the determination of A from also beingbased on C. In other instances, A may be determined based solely on B.

DETAILED DESCRIPTION

Wireless communication systems using high-frequency waves maycommunicate large amounts of data between devices. For example,millimeter waves having wavelengths between 1 millimeter and 10millimeters (e.g. 30-300 GHz waves) may communicate data at rates at orgreater than 1 gigabit per second. However, such waves may not be ableto effectively penetrate walls or solid structures, in somecircumstances. Also, a user of a device sending or receiving suchhigh-frequency waves may block the waves by positioning the user's bodyor a part of the user's body between a transmitter and receiver of thewave. Objects, humans, and pets between a transmitter and receiver may,for example, block or otherwise disrupt the signal. In addition, a userof a device sending or receiving such waves may move the device suchthat a solid structure blocks a current link between a transmitter and areceiver. Additionally, in multi-user systems other users may positionthemselves or other objects in a link between a transmitter and receiverof such high-frequency waves, such that a high-frequency wave is blockedby the other user or the other objects.

Often when a communication link is established between a transmitter andreceiver using a millimeter wave, such as between a user device and abase station, the transmitter and the receiver perform a scan or sweepoperation to determine a best direction for the transmitter to direct amillimeter wave that is directed to the receiver, (e.g. a best link).For example, though millimeter waves may not effectively penetrate wallsor other solid structures, millimeter waves may be reflected off of awall, floor, ceiling etc. Thus, if a direct line of sight is notavailable between a transmitter of a millimeter wave and a receiver,other links, such as those using a reflection off of a surface may bechosen as alternative links to a clear line-of-sight link.

Also, a transmitter of a millimeter wave may include antenna arrays totransmit and receive millimeter wave signals. In such systems, differentcombinations of sending and receiving antenna elements and configurableparameters of such antenna elements may be adjusted to form adirectional wave signal between a transmitter and a receiver (e.g., byapplying a phase shift or amplitude-weight vector (AWV) to redirect thetransmission of waves to shape the direction at which the wave signal istransmitted). Also, such systems may test different combinations ofantenna elements and configurable parameters of the antenna elements todetermine a best link from a transmitter to a receiver, such as a linkbetween a base station and a user device. For example, a transmitter maydetermine a direction to transmit a millimeter wave that results inbetter reception of the millimeter wave at the receiver as compared toother directions. Such scans or sweeps may be performed to initiallyestablish a link between a transmitter of a millimeter wave and areceiver of the millimeter wave. Also, such scans or sweeps may be atleast partially repeated each time a current link is obstructed and anew link is established. In many cases, such scans or sweeps may take anon-trivial amount of time to perform, and for many applicationsinterruptions in communication while such scans or sweeps are beingperformed may prevent the application from functioning properly. Forexample, when a link is obstructed, data exchange between a transmitterand receiver, such as a user device and a base station, may beinterrupted until a scan or sweep is completed and a new link isestablished between the transmitter and the receiver. Such interruptionsmay cause poor performance of an application operating on a user deviceand may negatively impact a user experience. For example, in streamingvideo or audio applications, such interruptions may cause a negativeuser experience. In streaming video or audio, the buffering in the videodisplay may be limited to reduce the cost. If the interruption is longerthan the duration of the buffering, the video display may be frozen. Forcertain interactive gaming applications, the interruption needs to be afraction of the interactive time. Otherwise, the video display maybecome unresponsive.

Various embodiments of different sector rotation speeds for post-ambleprocessing of a beam forming packet are described herein. The downtimeor latency devices experience to establish or re-establish communicationlinks between devices may be significantly reduced by performingdifferent sector rotation speeds for post-amble processing of a beamforming packet, which may reduce the number of transmissions (e.g.,packets) between devices in order to determine an optimal direction of acommunication link via a millimeter wave signal transmitted and receivedvia identified transmission and reception sectors. Post-amble processingmay, in various embodiments, be processing of data included in a portionof a data packet that occurs after a payload of the packet. For example,post-amble portions of the packet may, for instance, be an automaticgain control (AGC) portion appended to a payload portion which may allowfor feedback for a receiving antenna to determine information based onthe signal transmitted in the AGC portion of the packet. Antenna arraysmay transmit or receive signals via sectors which may identify thedirection to which the transmission or reception elements of the antennaarray are directed. A sector may, in various embodiments, identify apattern, shape, or other direction for transmitting or receiving thewave radiation (e.g., radio frequency (RF) signals, like millimeterwaves) via antenna (e.g., using multiple antennas in an antenna array).To determine an optimal direction of a communication link, both atransmission sector for a wireless communication device and a receptionsector for the other wireless communication device may be determined.

FIG. 1A illustrates an example transmission to begin determining theoptimal transmission (TX) and reception (RX) sectors, according to someembodiments. Wireless communication device 110, transmitter (TX), mayprepare to begin transmission of a packet for determining the TX and RXsectors. Sector rotation pattern 130 may be provided to wirelesscommunication device (RX) 120, so that wireless communication device 120can capture power measurements for the different transmission sectorsaccording to the sector rotation pattern at a different rotation speed,as discussed below with regard to FIGS. 1B and 3-6. Sector rotationpattern 130 may be provided as part of the same packet that includespost-amble transmission 140 according to sector rotation pattern 130(e.g., via a preamble, header, or payload as discussed below with regardto FIG. 3) or may be provided as part of a setup operation, as discussedbelow with regard to FIG. 5. Some parameters of the sector rotationpattern, for example, may be provided as the capabilities of thewireless communication devices in the association process.

FIG. 1B illustrates an example of different rotation speeds forpost-amble transmission of beam forming packet, according to someembodiments. Antenna array sectors 150 may provide a logicalillustration of different antenna array TX sectors for a wirelesscommunication device (TX) 110. Antenna array sectors 160 may provide alogical illustration of antenna array sectors for wireless communicationdevice (RX) 120. Sector rotation speeds for each antenna array maydiffer, in various embodiments. For example, transmitter sector rotationspeed 170 shows complete rotations through all antenna array sectors150, complete rotation 172 a, 172 b, 172 c through 172 y. However,receiver sector rotation speed 180 may perform a single completionrotation 182 in the same period of time (or overlapping periods oftime). In this way, power measurements 190 for one receiver antennaarray sector 160 can be captured for each antenna array sector 150, insome embodiments. For example, power measurements 190a may be capturedfor each antenna array sector 150 as it rotates according to receiversector rotation speed 170, while the first sector of antenna arraysectors 160 remains.

At the time the rotation to the next antenna array sector of antennaarray sectors 160 occurs, rotation may begin again for antenna arraysectors 150. Such differing rotation speeds may allow similar powermeasurements, such as power measurements 190 b and 190 c through 190 y,to be captured, allowing for an optimal receiver sector at wirelesscommunication device 120 to be selected based on the captured powermeasurements. Note that although FIG. 1B illustrates synchronizedrotations, with a complete rotation 172 aligning with a rotation to anew sector in antenna array sectors 160, in other embodiments, therotations need not be synchronized. Antenna array sectors 160 could, forexample rotate half-way through the complete rotation 172 of antennaarray sectors 150 and still capture power measurements for each antennaarray sector 150. Thus, the logical illustration provided in FIG. 1B isnot intended to be limiting as to the synchronization of sectorrotations at different wireless devices, but merely illustrates anexample of the differing rotation speeds. FIG. 1B shows only onereceiving antenna array, for example. For a wireless device havingmultiple antenna arrays, all arrays in 120 may rotate theircorresponding sectors simultaneously to capture power measurements forall sectors in all antenna arrays, in some embodiments.

FIG. 2 illustrates a wireless communication device that implementsdifferent sector rotation speeds for post-amble processing of a beamforming packet, according to some embodiments. Wireless communicationdevice 200 may be implemented, in some embodiments, to provide wirelesscommunications for host 210 (e.g., over millimeter wave radiofrequencies). As discussed below with regard to FIG. 7, host 210 mayimplement a network interface (e.g., a network interface card (NIC))which may generate, send, and receive data over a network usingdifferent networking protocols which may be established wirelesscommunication links established and maintained by wireless communicationdevice 300.

Wireless communication device 200 may be implemented as part of a largercircuit for host 210 or component or may be a separate circuit orhardware component connected to host 210. For example, some or all ofwireless communication device 200 may be implemented on dedicatedcircuitry or hardware, including, but not limited to, an ApplicationSpecific Integrated Circuit (ASIC), system-on-a-chip (SoC), or fieldprogrammable gate array (FPGA), among others. Wireless communicationdevice 200 may implement broadband processing 220, in some embodimentswhich may include a processor (e.g., such as processor 1010 in FIG. 7)and memory (e.g., such as memory 1020 in FIG. 7) and/or dedicatedcircuitry to perform digital processing of radio frequency (RF) signalsreceived via antenna arrays 230. Broadband processing 220 may performvarious management or request-handling operations to implementcommunications to and from host 210 (e.g., via a network interface likenetwork interface 1040 in FIG. 7).

Broadband processing 220 may, in some embodiments, implement beamforming processing 222. Beam forming processing 222 may manage beamforming processing for establishing communication links with otherwireless communication devices using directed RF communications (e.g.,millimeter wave beams). For millimeter wave beams, broadband processing220 may implement different techniques for establishing, maintaining,and recovering communication links. Beam forming 222 may, for instance,perform sector level sweeps to identify optimal sectors to utilize fortransmitting and receiving a millimeter wave beam to another wirelesscommunication, in some embodiments. Multiple short packets, sector sweep(SSW) frames, may be sent from individual sectors to an antenna array atanother wireless communication device that may receive the packetsutilizing an omnidirectional antenna pattern. Beam forming 222 mayimplement beam tracking to find an optimal receiver amplitude weightvector (AWV) after an optimal transmitter sector has been identified, insome embodiments.

Beam forming 222 may implement beam refinement protocol (BRP)techniques, in some embodiments. BRP techniques may utilize a post-ambleportion of a packet sent from an initiator to a responder (anotherwireless communication device implementing an antenna array). In someBRP techniques, the post-amble portion may include information thatprovides a training field, transmitted via one of the transmissionsectors or AWV of an initiator. Based on the channel measurement at thepost-amble of the packets, an optimal receiver sector or AWV may bedetermined for receiving millimeter wave beams between the initiator andresponder. In some BRP techniques, the post-amble portion may change thetransmitted AWV to test various orientations to conduct channelmeasurement. Based on the response from the receiver back to thetransmitter, an optimal transmitter sector or AWV may be determined fordirecting millimeter wave beams between the initiator and responder. Forsome BRP techniques, only received training may be used and thecorresponding transmitter AWV of the same station may be determined byreciprocity.

While sector level sweeps and BRP techniques may provide different waysto determine an optimal direction for a millimeter wave beam (e.g., bydetermining a pair of optimal phase vectors or AWV to shape thetransmission and reception to achieve the optimal direction for thebeam), latency sensitive applications may be unable to wait for suchtechniques to determine an optimal direction for a millimeter wave beam,as noted above. In various embodiments, beam forming 222 may implementdifferent sector rotation speeds for post-amble processing of a beamforming packet to significantly reduce the number of packets (e.g., totwo packets as illustrated in FIG. 3) according to the techniquesdiscussed below with regard to FIGS. 3-6. Instead of exchanging manypackets, as with the other BRP and sector sweep techniques discussedabove, a beam forming technique that implements different sectorrotation speeds for post-amble processing of a beam forming packet cansignificantly reduce the latency to determine an optimal direction for amillimeter wave beam between two wireless communication devices (e.g.,an 75% reduction in latency).

Wireless communication device 200 may implement antenna array(s) 230, invarious embodiments, which may include both transmitters 240 andreceivers 250 for transmitting and receiving RF signals (e.g.,millimeter waves). Transmitter 240 may implement digital to analogconverter (DAC) 241. DAC 241 may receive digital signals from broadbandprocessing 220 and convert the digital signal into an analog signal.Mixer 243 and splitter 245 may split the analog signal for transmissionvia separate antennas. Phase shifter 247 may implement a phase vector totime the transmission of the analog signals via the different antennasin order to create a desired beam direction or shape (e.g., to transmitthe wireless beam via a particular sector). Power amplifiers (PA) 249may amplify the signal power prior to transmission via the antennas. Inone embodiment, phase shifter 247 may comprise of amplitude adjustmentfor a full implementation of AWV in both amplitude and phase. Similarly,antenna array(s) 230 may implement receiver 250 which may receive an RFsignal via antennas, increase the power of the signal via a low noiseamplifier (LNA) 259, shape the timing of signals via phase shifter 257(e.g., according to a phase vector to direct the receipt of the signalusing a particular receiver sector specified by the phase vector),combine the signal using combiner 255 and mixer 243, and convert theanalog signal to a digital signal via analog to digital converter (ADC)241, in some embodiments.

Host 210, which may implement or connect to wireless communicationdevice 200 may implement wireless communication device as part of alarger circuit, chip, or other host hardware or may be coupled to thewireless communication device. Host 210 may, in some embodiments,program or otherwise specify control settings or configurations forwireless communication device 200, such as enabling various types ofbeam forming techniques, including enabling or disabling BRP techniquesthat utilize different sector rotation speeds for post-amble processingof a beam forming packet, as discussed below. In at least someembodiments, host 210 may be implemented as part of a wirelesscommunication system that utilizes multiple different relay docks orstations, user devices (e.g., wearable mobile computing devices), andbase stations, among others.

FIG. 3 illustrates example beam forming packets that may be transmittedimplementing different sector rotation speeds for post-amble processingof a beam forming packet, according to some embodiments. Initiator 310may be a wireless communication device, like wireless communicationdevice 200 in FIG. 2., that may initiate a beam forming with responder320, which may be another wireless communication device (e.g., similarto or different than communication device 200) as responder. Forexample, initiator 310 may be a wireless access device, such as router,relay device, or other networking device, and responder 320 may be amobile computing device (e.g., a laptop, mobile phone or wearabletechnology), or vice versa.

Initiator 310 may generate packet 340, which may be a beam formingpacket that includes fields, portions, or sections for implementingdifferent sector rotation speeds for post-amble processing of a beamforming packet, in some embodiments. For example, packet 340 may includepreamble 342, header 344, and payload 346, which may communicate variousinformation about initiator 310 and the beam forming to be performed,such as a rotation speed and a pattern for transmitting from sectors atinitiator 310, as well as other information usable for other functionsor by other devices. For example, other devices may intercept the packetand be able to use payload 346 information to perform navigation (e.g.,for wireless triangulation techniques). In some embodiments, thepreamble 342, header 344, and payload 346 may just serve as an indicatorto other devices in the network to signal the duration of the packet 340to avoid packet collision in the air.

Transmission of packet 340 may include a post-amble portion, which mayoccur once payload transmission 346 is concluded. Thus, in someembodiments, data of packet 340 prior to the post-amble period may betransmitted according to a pre-determined optimal transmission sector.Once post-amble processing begins, transmission of packet 340 may beperformed according to a rotation pattern and rotation speed, asdiscussed above with regard to FIGS. 1A-1B. The post-amble period ofpacket 340 may include an automatic gain control (AGC) portion 348 whichmay include test fields for performing power measurement. Transmitter(TX) sectors 352 may be transmitted according to a rotation pattern(e.g., sector 1, 2, 3, and so on till sector N) which may be repeatedaccording to the number of receiver (RX) sectors 354 of responder (e.g.,denoted from 1 to M), in some embodiments.

As discussed in detail below with regard to FIGS. 4-6, responder 320 mayprocess the received packet 340, rotating RX sectors so as to capturepower measurements for each of the TX sectors at each RX sector beforerotating to a next RX sector. In some embodiments, the synchronizationof TX sector rotations can be sufficiently accurate (e.g., above aconfidence threshold or in response to receiving the preamble 342,header 344, and payload 346 prior to AGC 348) to determine both anoptimal RX sector at responder 320 and TX sector at initiator 310 basedon the captured power measurements. In such scenarios, responder 320 mayrespond to initiator 310 indicating the optimal TX and RX sector in apacket communication (not illustrated) as a response to the packet 340.

In scenarios where the synchronization of TX sector rotations is notsufficiently accurate, then responder 320 may generate a packet 360 toperform further beam forming with initiator 310 in order to determine aTX sector at initiator that is optimal for communication betweeninitiator 310 and responder 320. As before, packet 360 may include apreamble 362, header, 354, and payload 366, some or all of which mayindicate rotation speed and pattern of transmission of sectors fromresponder 320 (e.g., 1 sector, the optimal RX sector 372), as well asother information usable for other functions or by other devices, insome embodiments. In some embodiments, the preamble 362 header 354, andpayload 366 may serve as an indicator to other devices in the network tosignal the duration of the packet 360 to avoid packet collision in theair.

In at least some embodiments, packet 360 may include an AGC portion 368which may include a test field using the optimal TX sector (determinedby responder 320 using the reciprocal sector of the RX sector atresponder 320 that received the signal with the greatest powermeasurement from initiator 310). In some embodiments with multipleantenna arrays in responder 320, the optimal antenna array having thegreatest power measurement in one of its sector may be used to transmitpacket 360. As discussed below with regard to FIG. 6, initiator 310 maythen sweep or otherwise rotate the RX sectors of initiator 310 tocollect power measurements, identify the sector with the greatest powermeasurement and perform reciprocity to determine the optimal TX sector,resulting in initiator 310 having determined the optimal TX sector touse for sending millimeter wave beams to responder 320 and responder 320having determined the optimal TX sector to use for receiving millimeterwave beams from initiator 310, in some embodiments. In some embodimentswith multiple antenna arrays in initiator 310, the antenna array withthe best performance may also be determined.

Although FIGS. 2-3 have been described and illustrated an examplewireless communication device and beam forming packet exchange, thevarious techniques and components illustrated and described in FIGS. 2-3may be easily applied to wireless communication devices. For example,wireless communication devices with a single antenna array or differentbroadband processing or radio frequency channel configurations mayimplement different sector rotation speeds for post-amble processing ofa beam forming packet. As such, FIGS. 2-3 are not intended to belimiting as to other embodiments of a wireless communication device thatmay implement different sector rotation speeds for post-amble processingof a beam forming packet.

FIG. 4 is a high-level flowchart illustrating various methods andtechniques to implement different sector rotation speeds for post-ambleprocessing of a beam forming packet, according to some embodiments.Various different wireless communication devices may implement thevarious methods and techniques described below, including FIGS. 5 and 6,either singly or working together. Therefore, the above examples and orany other systems or devices referenced as performing the illustratedmethod, are not intended to be limiting as to other differentcomponents, modules, systems, or configurations of systems and devicesthat transmit or receive radio frequency signals.

Different events may trigger beam forming evaluation. For example,signal strength of a link between wireless communication devices mayfall below a threshold value or failure of a signal or communicationlink between wireless devices may be detected, in some embodiments. Insome embodiments, multiple types of beamforming evaluations or protocolsmay be implemented in wireless devices. Intelligent selection of a typeof beam forming protocol may be performed based, at least in part, onthe event that triggers beam forming evaluation. For example,configuration settings or other modes for a wireless communicationdevice may be set which determine whether beam forming evaluationtechniques, such as those discussed below with regard to FIGS. 4-6, areperformed in the event of a beam forming evaluation, or if other beamforming refinement protocols are utilized (e.g., BRP protocols specifiedfor IEEE 802.11 standards, such as 802.11ad or 802.11ay).

Beam forming evaluation may begin as a result of the transmission a beamforming protocol packet, in some embodiments. As indicated at 410,respective power measurements of millimeter wave beams between a sectorof a first antenna array between a sector of a first antenna arrayrotating at a first rotation speed to receive a packet (e.g., the BRPpacket) and sectors of a second antenna array rotating at secondrotation speed. The difference in rotation speeds between the sectors ofthe antenna arrays may be determined according to a rotation pattern forthe second antenna array. For example, if the rotation pattern for thesecond antenna array indicates that it will complete a cycle ofrotations through all sectors of the second antenna array within time X,then the rotation speed of the first antenna may be determined so thateach rotation of a sector for the first antenna may cover all of thesectors of the second antenna array. In one embodiment as shown in FIG.3, the duration of X may include the rotation of 1 to N sectors inpacket 340 of FIG. 3. Thus, in at least some embodiments, the firstrotation speed may be slower than the second rotation speed (e.g., firstrotation speed per sector time Y, which may be longer than secondrotation speed for all sectors X such that the first rotation cancapture all variations of the second rotation, see example of 190 a, . .. , 190 y in FIG. 1B). In one embodiment, as shown in FIG. 3, theduration of Y may be equal to rotations between sectors 1 to M forpacket 340. Power measurements of the millimeter wave beams may becaptured and stored for subsequent analysis, in some embodiments. Insome embodiments, only some of the determine power measurements may beretained. For example, as discussed below with regard to FIGS. 5 and 6,multiple power measurements for a sector may be determined, with onlythe greatest power measurement retained for comparison with the powermeasurements of other sectors.

Once the power measurements are determined, the first antenna may rotateto the next sector of the first antenna array, as indicated at 420, ifthe sector at the first antenna array is not the last sector, asindicated by the negative exit from 420. If, however, the sector of thefirst array is the last sector, then as indicated at 430, the powermeasures may be evaluated to select one of the sectors at the firstantenna array with a greatest power measurement. For example, the powermeasures may be stored or associated with individual sectors at thefirst array. The stored measures may be scanned to locate the sectorassociated with the greatest power measurement.

As indicated at 440, a millimeter wave beam may be directed from thefirst antenna array or the second antenna array that uses the selectedsector, in some embodiments. For example, the above beam formingevaluation techniques may be implemented between an initiating wirelesscommunication device and a responding wireless communication device. Theinitiating wireless communication device may send the packet indicatinga rotation pattern of TX sectors that is performed once, cycling throughall TX sectors in X time. Based on the pattern indication of performanceof a single cycle, the responding wireless communication device maydetermine a rotation speed that is fast to complete an entire cycle ofreceiving sectors in the time it takes to complete one transmittingsector at initiator (e.g., responder rotations speed=(X/number of TXsectors at initiator)/number of sectors at responder), in someembodiments. Alternatively, as discussed below with regard to FIGS. 5and 6, the initiator may indicate a rotation pattern that performsmultiple complete cycles of TX sectors in X time, which the initiatorcan use to determine the speed in which to rotate between each RX sectorin a single cycle. Millimeter wave beams may be directed by programmingor configuration phase shifts to transmit and receive signals from therespective antenna arrays according to phase vectors that can direct themillimeter beams to the identified sectors.

In some scenarios, as noted above, either the initiator or the respondermay perform a rotation of sectors according to a rotation speed thatallows the other to send to or receive from a complete rotation ofsectors so that power measurements for millimeter wave beams between theset of sectors at one antenna array and one of the sectors of the otherantenna array may be determined. In one embodiment, a wirelesscommunication device that is an initiator of beam forming may performthe complete rotation of sectors at speed to take measurements for eachsector of a wireless communication device that is a responder. FIG. 5 isa high-level flowchart illustrating various methods and techniques toselect an optimal reception sector at a responder receiving a packet ofa beam forming protocol, according to some embodiments.

As indicated at 510 and 512, initiator 502 and responder 504, mayperform setup operations to accomplish beam forming. For example, setupmay include establishing communications between the initiator 502 andresponder 504, such as by sending a control PHY packet from either theinitiator to responder 504, or from responder 504 to initiator. Setupmay be performed prior to link degradation, loss, or other trigger eventthat is causes initiator 502 to begin beam forming with responder 504,in some embodiments. Setup operations may be periodically performed, orin response to other events (e.g., completion of a beacon broadcast byeither initiator 502 or responder 504, or if a non-BRP packet is notreceived within a period of time). Setup may include the exchange ofinformation that can indicate a rotation pattern and/or speed forinitiator 502 so that responder 504 can determine a rotation speed forrotating between RX sectors (e.g., sector rotation occurs every T μs).In one embodiment, the setup operations may be defined in certainpre-defined anchor points. If no packet is detected at or immediatelyprior to the anchor points, setup operation may be implicitlyestablished, in some embodiments.

As indicated 520, initiator 502 may transmit a packet to responder 504,rotating between TX sectors in the post-amble according to a sectorrotation pattern and first rotation speed, in some embodiments. Forexample, as discussed above with regard to FIG. 3, the post-amblerotation of an antenna array of initiator 502 may include respectivetraining fields within the AGC field, in some embodiments. The preamble,header, and/or payload of the packet may be received at responder 504,in some embodiments, indicating the rotation pattern and/or speed forthe post-amble transmission of initiator 520, in some embodiments, inlieu of or to replace such information that may have been obtained whenperforming setup (e.g., at elements 510 and 512 respectively). Asindicated at 522, responder 504 may set a first RX sector to receive thepacket the beginning of the post-amble.

As indicated at 530, a power measurement for a time period T may bedetermined, in some embodiments, by responder 504. Time period T may beset according to a desired number of power measurements to obtain for aTX sector of initiator 502 (e.g., longer time period for more powermeasurements and shorter time period for less power measurements) andthus T may be less than or equal to a period of time that a single TXsector is transmitted before rotating to a next TX sector at initiator502 in the post-amble. A determined power measurement may be comparedwith other power measurements for the RX sector. As indicated at 542, ifthe power measurement is not the greatest power measurement determinedfor the RX sector, the power measurement may move forward. If, however,as indicated by the positive exit from 540, the power measurement is thegreatest power measurement determined for the RX sector, then the powermeasurement may be saved, as indicated at 550.

Power measurements may continue to be determined and compared with otherpower measurements for a current RX sector at responder 504 until, asindicated at 560, the time elapsed since the current RX sector was setis greater than a time to complete TX sector rotation at initiator 520.If the current RX sector is not the last RX sector, as indicated by thenegative exit from 570, then a next RX sector to receive the packet 562may be set at responder to continue processing the post-amble of thepacket received from initiator 502. If the RX sector is the last RXsector, then the saved power measurements may be evaluated to identifythe RX sector with a greatest power measurement, in some embodiments, asindicated at 580. In some embodiments where a responder has multipleantenna arrays, all the antenna arrays may have its sectors rotatesimultaneously to determine both the RX sectors and the correspondingarray having the largest measurement power.

As discussed above with regard to FIGS. 4 and 5, in some scenarios, someor all of the preamble, header, and/or payload of a BRP packet sent froman initiator to another wireless communication device may not bereceived or detected at a responder. However, beam forming can continueby sending a responsive packet to the initiator, allowing the initiatorto determine which sector of the initiator to target with a millimeterwave beam. FIG. 6 is a high-level flowchart illustrating various methodsand techniques to select an optimal transmission sector for an initiatorof a beam forming protocol, according to some embodiments.

As indicated at 610, one of the transmission (TX) sectors of theresponder 504 may be selected based on the RX sector of the responder504 that was determined to have the greatest power measurement, in someembodiments. For example, the reciprocal TX sector at responder 504 maybe identified according to the selected RX sector. As indicated at 620,a packet indicating the selected TX sector may be transmitted using theselected TX sector. As part of transmitting the beam forming packet,responder 504 may perform a post-amble transmission that lasts for atime T1, in some embodiments. As noted above in FIG. 3, the beam formingpacket may include an AGC field, different portions of which allow therotation of RX sectors of initiator 502. The post-amble transmission mayperform a rotation between the different TX sectors of responder 504that is completed at time period T1.

Although not illustrated in FIG. 6, in some embodiments, initiator 502may not receive the packet from responder 504. Error handling may beimplemented in the event a failure occurs during the beam formingprocess. For example, an elapsed time threshold may be evaluated at theinitiator 502. If a packet from responder 504 is not received within theelapsed time threshold, then initiator 502 may assume a failure in thereceipt of the first packet, and re-try by resending the packet (e.g.,according to the packet transmission techniques discussed above withregard to element 520 of FIG. 5), in some embodiments.

Initiator 502 may set a first RX sector to receive the packet at thebeginning of the post-amble phase, in some embodiments. A powermeasurement for a time period T2 may be determined, as indicated at 630.Time T2 may be set according to the number of desired power measurementsfor a sector. If, for example, multiple power measurements are desired,then the difference between T2 and the total time to perform a sectorrotation (e.g., time T3 as discussed below) may be increased.Alternatively, if, for instance, a single power measurement is desiredfor each RX sector, then time T2 may be set to approximately equal thetotal time to perform the RX sector rotation (e.g., where T2 T3). If thedetermined power measurement is not greater, then the power measurementmay be ignored, as indicated at 642. If the determined power measurementis greater than any other determined for the set RX sector, the powermeasurement may be saved for further evaluation (e.g., in a memory,register, or other location), as indicated at 650.

Power measurement determination(s) for the current RX sector maycontinue until a time elapsed since the RX sector was set is greaterthan a time T3 to rotate the RX sector at responder 504, as indicated at660. Time T3 may be determined in various ways. For instance, time T3may be approximately equal to the total time of the post-amble dividedby the number of RX sectors at initiator 502 (e.g., T3≈T1/N sectors). Ifthe time has not elapsed, then as indicated by the negative exit from660, further power measurements may be determined. If the time haselapsed, then a determination may be made as to whether the current RXsector is the last RX sector initiator 502. If not, then a next RXsector may be selected to receive the packet, as indicated at 662. Ifso, as indicated a t680, then saved power measurements may be evaluatedto identify the RX sector with a greatest power measurement.

FIG. 7 is a logical block diagram of an example computer system,according to some embodiments. The computer system 1000 may beconfigured to execute, include, or implement a host, wireless computingdevice, or perform any or all of the embodiments described above. Indifferent embodiments, computer system 1000 may be any of various typesof devices, including, but not limited to, a personal computer system,desktop computer, laptop, notebook, tablet, slate, pad, or netbookcomputer, mainframe computer system, handheld computer, workstation,network computer, a camera, a set top box, a mobile device, a consumerdevice, video game console, handheld video game device, applicationserver, storage device, a television, a display device, a videorecording device, a peripheral device such as a switch, modem, router,or in general any type of computing device, computing node, orelectronic device.

Computer system 1000 includes one or more processors 1010 coupled to asystem memory 1020 via an input/output (I/O) interface 1030. Computersystem 1000 further includes a network interface 1040 coupled to I/Ointerface 1030, which may establish network connections over wirelesscommunication device 1042 (as discussed above with regard to FIG. 2and/or wired communication device 1044, and one or more input/outputdevices 1050, such as cursor control device 1060, keyboard 1070, anddisplay(s) 1080. In some cases, it is contemplated that embodiments maybe implemented using a single instance of computer system 1000, while inother embodiments multiple such systems, or multiple nodes making upcomputer system 1000, may be configured to host different portions orinstances of embodiments. For example, in one embodiment some elementsmay be implemented via one or more nodes of computer system 1000 thatare distinct from those nodes implementing other elements (e.g., anotherdevice implementing another wireless communication device).

In various embodiments, computer system 1000 may be a uniprocessorsystem including one processor 1010, or a multiprocessor systemincluding several processors 1010 (e.g., two, four, eight, or anothersuitable number). Processors 1010 may be any suitable processor capableof executing instructions. For example, in various embodimentsprocessors 1010 may be general-purpose or embedded processorsimplementing any of a variety of instruction set architectures (ISAs),such as the x86, PowerPC, SPARC, or MIPS ISAs, or any other suitableISA. In multiprocessor systems, each of processors 1010 may commonly,but not necessarily, implement the same ISA.

System memory 1020 may be configured to store program instructions 1022and/or other data accessible by processor 1010. In various embodiments,system memory 1020 may be implemented using any suitable memorytechnology, such as static random access memory (SRAM), synchronousdynamic RAM (SDRAM), nonvolatile/Flash-type memory, or any other type ofmemory. In the illustrated embodiment, program instructions 1022 may beconfigured to implement an image sensor control applicationincorporating any of the functionality described above. In someembodiments, program instructions and/or data may be received, sent orstored upon different types of computer-accessible media or on similarmedia separate from system memory 1020 or computer system 1000. Whilecomputer system 1000 is described as implementing the functionality offunctional blocks of previous Figures (e.g., via a wirelesscommunication device or similar features or components), any of thefunctionality described herein may be implemented via such a computersystem.

In one embodiment, I/O interface 1030 may be configured to coordinateI/O traffic between processor 1010, system memory 1020, and anyperipheral devices in the device, including network interface 1040 orother peripheral interfaces, such as input/output devices 1050. In someembodiments, I/O interface 1030 may perform any necessary protocol,timing or other data transformations to convert data signals from onecomponent (e.g., system memory 1020) into a format suitable for use byanother component (e.g., processor 1010). In some embodiments, I/Ointerface 1030 may include support for devices attached through varioustypes of peripheral buses, such as a variant of the Peripheral ComponentInterconnect (PCI) bus standard or the Universal Serial Bus (USB)standard, for example. In some embodiments, the function of I/Ointerface 1030 may be split into two or more separate components, suchas a north bridge and a south bridge, for example. Also, in someembodiments some or all of the functionality of I/O interface 1030, suchas an interface to system memory 1020, may be incorporated directly intoprocessor 1010.

Network interface 1040 may be configured to allow data to be exchangedbetween computer system 1000 and other devices attached to a network1085 (e.g., carrier or agent devices) or between nodes of computersystem 1000. Network 1085 may in various embodiments include one or morenetworks including but not limited to Local Area Networks (LANs) (e.g.,an Ethernet or corporate network), Wide Area Networks (WANs) (e.g., theInternet), wireless data networks, some other electronic data network,or some combination thereof. In various embodiments, network interface1040 may support communication via wired or wireless general datanetworks, such as any suitable type of Ethernet network, for example;via telecommunications/telephony networks such as analog voice networksor digital fiber communications networks; via storage area networks suchas Fiber Channel SANs, or via any other suitable type of network and/orprotocol. Wired communication device 1044 may connect computing system1000 via a cable (e.g., coaxial cable, twisted pair cable, or fiberoptic link) to another networking device (e.g., router, switch, hub,etc.) which may over the course of one or multiple wired or wirelesscommunication paths connect computing system 1000 to network 1085.Wireless communication device 1044, as discussed above with regard toFIG. 3 may implement radio wave communications to establishcommunication channels with other wireless enabled devices to providenetwork communications.

Input/output devices 1050 may, in some embodiments, include one or moredisplay terminals, keyboards, keypads, touchpads, scanning devices,voice or optical recognition devices, or any other devices suitable forentering or accessing data by one or more computer systems 1000.Multiple input/output devices 1050 may be present in computer system1000 or may be distributed on various nodes of computer system 1000. Insome embodiments, similar input/output devices may be separated fromcomputer system 1000 and may interact with one or more nodes of computersystem 1000 through a wired or wireless connection, such as over networkinterface 1040.

As shown in FIG. 7, memory 1020 may include program instructions 1022,which may be processor-executable to implement any element or actiondescribed above. In one embodiment, the program instructions mayimplement the methods described above. In other embodiments, differentelements and data may be included. Note that data may include any dataor information described above.

Those skilled in the art will appreciate that computer system 1000 ismerely illustrative and is not intended to limit the scope ofembodiments. In particular, the computer system and devices may includeany combination of hardware or software that can perform the indicatedfunctions, including computers, network devices, Internet appliances,PDAs, wireless phones, pagers, display devices, etc. Computer system1000 may also be connected to other devices that are not illustrated, orinstead may operate as a stand-alone system. In addition, thefunctionality provided by the illustrated components may in someembodiments be combined in fewer components or distributed in additionalcomponents. Similarly, in some embodiments, the functionality of some ofthe illustrated components may not be provided and/or other additionalfunctionality may be available.

Those skilled in the art will also appreciate that, while various itemsare illustrated as being stored in memory or on storage while beingused, these items or portions of them may be transferred between memoryand other storage devices for purposes of memory management and dataintegrity. Alternatively, in other embodiments some or all of thesoftware components may execute in memory on another device andcommunicate with the illustrated computer system via inter-computercommunication. Some or all of the system components or data structuresmay also be stored (e.g., as instructions or structured data) on acomputer-accessible medium or a portable article to be read by anappropriate drive, various examples of which are described above. Insome embodiments, instructions stored on a computer-accessible mediumseparate from computer system 1000 may be transmitted to computer system1000 via transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as a network and/or a wireless link. Various embodiments mayfurther include receiving, sending or storing instructions and/or dataimplemented in accordance with the foregoing description upon acomputer-accessible medium. Generally speaking, a computer-accessiblemedium may include a non-transitory, computer-readable storage medium ormemory medium such as magnetic or optical media, e.g., disk orDVD/CD-ROM, volatile or non-volatile media such as RAM (e.g. SDRAM, DDR,RDRAM, SRAM, etc.), ROM, etc. In some embodiments, a computer-accessiblemedium may include transmission media or signals such as electrical,electromagnetic, or digital signals, conveyed via a communication mediumsuch as network and/or a wireless link.

The methods described herein may be implemented in software, firmware,hardware, or a combination thereof, in different embodiments. Inaddition, the order of the blocks of the methods may be changed, andvarious elements may be added, reordered, combined, omitted, modified,etc. Various modifications and changes may be made as would be obviousto a person skilled in the art having the benefit of this disclosure.The various embodiments described herein are meant to be illustrativeand not limiting. Many variations, modifications, additions, andimprovements are possible. Accordingly, plural instances may be providedfor components described herein as a single instance. Boundaries betweenvarious components, operations and data stores are somewhat arbitrary,and particular operations are illustrated in the context of specificillustrative configurations. Other allocations of functionality areenvisioned and may fall within the scope of claims that follow. Finally,structures and functionality presented as discrete components in theexample configurations may be implemented as a combined structure orcomponent. These and other variations, modifications, additions, andimprovements may fall within the scope of embodiments as defined in theclaims that follow.

What is claimed is:
 1. A system, comprising: a first and second wirelesscommunication device, respectively comprising a broadband processor andone or more antenna arrays; the first wireless communication device,configured to: transmit a packet to the second wireless communicationdevice, wherein the transmission of a post-amble portion of the packetis performed according to first rotation speed and a rotation patternbetween a plurality of transmission sectors of the one or more antennaarrays at the first wireless communication device; the second wirelesscommunication device, configured to: rotate between reception sectors ofthe one or more antenna arrays at the second wireless communicationdevice according to a second rotation speed that is different than thefirst rotation speed to capture power measurements between individualones of the reception sectors and the transmission sectors based on thereceipt of the post-amble portion of the packet from the first wirelesscommunication device; compare the power measurements to identify one ofthe reception sectors at one of the one or more antenna arrays at thesecond wireless communication device with a greatest power measurement;and transmit a second packet to the first wireless communication deviceusing a transmission sector at one of the one or more antenna arrays atthe second antenna array selected according to the identified receptionsector.
 2. The system of claim 1, wherein the second packet identifiesone of the transmission sectors at one of the one or more antenna arraysat the first wireless communication device and the identified receptionsector at the one antenna array at the second wireless communicationdevice for establishing an optimal millimeter wave beam between thefirst and second wireless communication devices.
 3. The system of claim1, wherein the second packet includes a post-amble portion; wherein thefirst wireless communication device is further configured to: rotatebetween reception sectors of the one or more antenna arrays at the firstwireless communication device to capture power measurements betweenindividual ones of the reception sectors of the one or more antennaarrays at the first wireless communication device and the transmissionsector of the second wireless communication device based, at least inpart, on the receipt of the post-amble portion of the second packet fromthe second wireless communication device; compare the power measurementsto identify one of the reception sectors of the first antenna array witha greatest power measurement; and select one of the transmission sectorsof the first antenna array according to the identified reception sectorof the first antenna array, wherein the selected transmission sector ofthe first antenna array and the identified reception sector of thesecond antenna array are usable to establish an optimal millimeter wavebeam between the first and second wireless communication devices.
 4. Thesystem of claim 1, wherein the first wireless communication device isfurther configured to: detect a failure or degradation of acommunication link between the first and second wireless communicationdevice; and perform the transmission of the packet in response to thedetection of the failure or degradation of the communication link. 5.The system of claim 1, further comprising a first host and a secondhost, wherein the first wireless communication device provides wirelesscommunication to the first host, wherein the second host provideswireless communication to the second host, and wherein data istransmitted between the first and second host using a millimeter wavebeam between the first and second wireless communication devicestransmitted based, at least in part, on the identified reception sectorat the second wireless communication device.
 6. A method, comprising:performing, by one or more wireless communication devices: forindividual ones of a plurality of sectors of a first antenna arrayrotating between the sectors at a first rotation speed to receive apacket: determining respective power measurements of millimeter wavebeams for a plurality of sectors of a second antenna array rotatingbetween the second sectors at a second rotation speed different than thefirst rotation speed; and evaluating the power measures to select one ofthe sectors at the first antenna array with a greatest power measurementof the respective power measurements; and directing transmission of amillimeter wave beam from the first antenna array or the second antennaarray that uses the selected sector.
 7. The method of claim 6, furthercomprising receiving the packet from the second antenna array, whereinthe packet includes a post-amble portion transmitted according to arotation pattern for rotating between the sectors of the second antennaarray.
 8. The method of claim 7, wherein the sectors of the secondantenna array are transmission sectors, wherein the sectors of the firstantenna array are reception sectors, and wherein the selected sector isone of the reception sectors used to receive the millimeter wave beamtransmitted from the second antenna array.
 9. The method of claim 8,further comprising: sending, by the first antenna array, a second packetto the second antenna array using a transmission sector at the secondantenna array identified according to the selected reception sector ofthe first antenna array; determining respective power measurements ofmillimeter wave beams between a plurality of reception sectors of thesecond antenna array and the identified transmission sector at the firstantenna array; and evaluating the respective power measures of themillimeter wave beams between the reception sectors of the secondantenna array and the identified transmission sector at the firstantenna array to select one of the reception sectors at the secondantenna array with a greatest power measurement; identifying one of thetransmission sectors at the second antenna array based on the selectedreception sector at the first antenna array; wherein the directing ofthe millimeter wave beam uses the identified transmission sector of thefirst antenna array and the identified reception sector of the secondantenna array transmit the millimeter wave beam.
 10. The method of claim7, wherein the sectors of the second antenna array are receptionsectors, wherein the sectors of the first antenna array are transmissionsectors, and wherein the selected sector is one of the transmissionsectors used to transmit the millimeter wave beam transmitted from thefirst antenna array to the second antenna array.
 11. The method of claim7, wherein the packet is sent from the second antenna array in responseto a determination that a wireless signal strength between a firstwireless communication device implementing the first antenna array and asecond wireless communication device implementing the second antennaarray is below a strength threshold.
 12. The method of claim 6, whereinthe determining, the evaluating, and the directing are performed inresponses to a determination that a type of beam forming protocol thatincludes the determining, the evaluating, and the directing is enabledfor respective wireless communication devices implementing the firstantenna array and the second antenna array.
 13. The method of claim 5,further comprising determining the first rotation speed based, at leastin part on a rotation pattern for rotating between the sectors of thesecond antenna array provided to a wireless communication deviceimplementing the first antenna array.
 14. A wireless communicationdevice, comprising a broadband processor and at least one antenna array,the wireless communication device configured to: perform a singlecomplete rotation amongst reception sectors of an antenna array toreceive a packet from another wireless communication device sent viaanother antenna array that includes a post-amble portion of multiplecomplete rotations of transmission sectors of the other antenna array;capture at least one power measurement of a millimeter wave beam betweenindividual ones of the reception sectors and the transmission sectorsfor different ones of the complete rotations of the transmissionsectors; evaluate the captured at least one power measurements for theindividual reception sectors to select one of the reception sectors witha greatest power measurement; and send another packet to the otherantenna array at the other wireless communication device using atransmission sector at the wireless communication device identifiedaccording to the selected reception sector.
 15. The wirelesscommunication device of claim 14, wherein the identified transmissionsector at the wireless communication device used to send the otherpacket is a reciprocal sector of the selected reception sector.
 16. Thewireless communication device of claim 14, further configured to performa setup operation with the other wireless communication device thatindicates a rotation speed for performing the complete rotations of thetransmission sectors of the other antenna array at the other wirelesscommunication device.
 17. The wireless communication device of claim 14,wherein the other packet identifies one of the transmission sectors ofthe other antenna array and the selected reception sector of the antennaarray for establishing an optimal millimeter wave beam between thewireless communication device and the other wireless communicationdevice.
 18. The wireless communication device of claim 14, wherein theother packet includes a post-amble portion for the other wirelesscommunication device to receive at different reception sectors of theother antenna array in order to identify one of the reception sectors ofthe other antenna array with a greatest power measurement capturedbetween the identified transmission sector at the antenna array and theone reception sector at the other antenna array, wherein a reciprocaltransmission sector of the identified one reception sector at the otherantenna array and the selected reception sector of the antenna array areused to establish an optimal millimeter wave beam between the wirelesscommunication device and the other wireless communication device. 19.The wireless communication device of claim 14, wherein a rotation speedfor performing the complete rotations of the transmission sectors of theother antenna array at the other wireless communication device isreceived as part of the packet.
 20. The wireless communication device ofclaim 14, wherein the packet is sent from the other wirelesscommunication device in response to a determination that a wirelesssignal strength between the wireless communication device and the otherwireless communication device is below a strength threshold.